


The Mystery of the Petrified Cat

by Lemikita



Category: Harry Potter - J. K. Rowling, Sherlock Holmes & Related Fandoms
Genre: Book 2: Harry Potter and the Chamber of Secrets, Crossover
Language: English
Status: Completed
Published: 2021-02-21
Updated: 2021-02-21
Packaged: 2021-03-18 14:21:56
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,405
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29610747
Author URL: https://archiveofourown.org/users/Lemikita/pseuds/Lemikita
Summary: What if a certain detective would take a look at the mysterious goings-on at Hogwarts?
Kudos: 4





	The Mystery of the Petrified Cat

“She's not dead, Argus,” he said softly.   
“Not dead?” choked Filch, looking through his fingers at Mrs Norris. “But why's she all – all stiff and frozen?”  
“She has been Petrified,” said Dumbledore “but how, I cannot say...”  
“Ask him!” shrieked Filch, turning his blotched and tear-stained face to Harry.  
“No second-year could have done this,” said Dumbledore firmly. “It would take Dark Magic of the most advanced kind. It seems, we have a crime and a mystery on our hands,” said Dumbledore, steepling his hands in a contemplative gesture. “Yes, I think it might be wise to consult with some experts on this.”  
Harry watched as the headmaster stepped over to the fireplace and lit it with a flick of his wand. He then took a small box from the mantle, opened it and took a pinch of something out of it only to immediately throw it into the flames.   
“Would you mind terribly, Gilderoy?” he asked as he ushered Lockhart off a rather fluffy rug “my knees don't agree with the current weather, you see.” Dumbledore placed the rug in front of the hearth to then kneel on it. He didn't hesitate as he stuck his head into the flames.   
From his place Harry couldn't understand what Dumbledore mumbled or hear any of the following exchange, but it wasn't long before he stood up, brushed off his robes and smiled silently. The teachers around him had apparently heard who he'd been talking to, but to the trio it was a surprise when the flames turned green once more and just a moment later two figures stepped out of the fireplace.  
The first to appear was a tall, stern looking, pale young man with black wavy hair, wearing beautiful dark blue robes. He was followed by a shorter, friendly looking man in somewhat worn robes. His dark blonde hair shimmered in the candle light as he looked around the room curiously.  
“Well, let's see if this is really worth my time,” the taller one remarked with a slight sneer. He stepped up to examine Mrs Norris, in a similar fashion to Dumbledore just minutes before. His companion followed and looked incredulously down at the cat.  
“This is what we came here for? A dead cat?” he scoffed.  
“Not dead, petrified.” The taller of the two corrected his companion and rose from his investigation of the animal. He smiled down at the other man. “Oh this is gonna be good, John, I haven't had a mystery like this in years! This is going to be marvellous!”   
“And you got all that from a petrified cat, Sherlock? How on eart- actually nevermind, the sooner we solve this, the sooner I can get back to my tea.”

* * *

Harry, Ron and Hermione had been told to go to their common room. After being dismissed as suspects by Dumbledore as well as Mr. Holmes and Mr. Watson, Ron had shared his knowledge of the pair. Apparently they were a famous pair of Aurors, working apart from the Ministry of Magic, solving mysteries and cases nobody else seemed to be able to solve. Mr. Watson even wrote about their cases in a column for the Daily Prophet which had led to an increased fame for both of them. Ron's mom was an avid fan of the pair.   
“Guess it's in good hands then,” Ron said as they climbed through the portrait hole.   
“I sure hope so. Are you sure they are capable and not just writing about heroic deeds, then?” Hermione had a sceptical look about her.   
Harry snickered as he saw Ron role his eyes behind Hermione's back.   
“Whoever gave you that idea?” Ron asked sarcastically. “It's not as if we know somebody who writes heroic books and doesn't seem to know anything.”   
“Professor Lockhart is very capable!” Hermione said in a stern voice. Her face softened. “I guess we'll give them the benefit of the doubt. I will still do my own research though. If only I hadn't left my copy of 'Hogwarts – A History' at home. Oh well, I'll go to the library tomorrow.”  
She said goodnight then and went to the girls dormitory.   
Ron and Harry ascended the stairs to their beds as well.  
“You really think that Holmes guy has this covered, Ron?”  
Ron shrugged as an answer. “I guess we'll have to see, right?”

* * * 

After Harry, Ron and Hermione had been dismissed, Sherlock turned to Dumbledore.   
“I assume you would like to see the crime scene now, wouldn't you, Mr. Holmes?” the headmaster surmised. “Very well, Professor McGonagall will show you. If you need anything, you know where to find me. It's the sour one this time.”   
McGonagall led the pair out of the classroom while the rest of the teachers and Mr. Filch stayed behind.   
“Well, my dear headmaster,” Gilderoy Lockhart exclaimed “you really didn't need to involve the two of them, I assure you. They may have solved The Case of the Vibrating Vampires well enough and they even managed to clear up that thing about the Three Orange Cauldrons, but as you well know, I did solve my fair share of mysteries – all collected in my upcoming special edition of 'Sleuthing with Selkies', and before you ask, of course you'll get signed copies – and I assure you that I will solve this in no time at all!”  
Dumbledore listened to his little speech with poise and politely nodded along. “Well, I'm sure you would have managed fine without them. However, you were hired for teaching, not for solving mysteries and the education of these fine students is far more important, I wouldn't want to disturb your lectures with any additional work.”   
“True, true. Alas, the children do so need my expert guidance, you are right. And if you believe these two to be capable... After all, I believe Mr. Watson has a book coming out, does he not?”

* * *

Professor McGonagall had led them along the corridor to the place where Mrs. Norris had been found.   
“I trust that you are in good health Professor? I haven't seen you since- well after the war we didn't stay in touch much” John commented.   
“Kind of you to ask, Mr. Watson, I am well, the circumstances permitting. I hope the same can be said about you? I heard about- well- you were with the Prewett brothers?”   
John touched his right shoulder pensively. “They were good people. I was lucky to get out.”  
McGonagall gave a tight laugh. “I don't think it was luck. You were always one of my best students.” She glanced at Sherlock. “Present company excluded.”  
Sherlock smirked. “You never liked me as much as John though, Professor.”  
She gave him an intense look which softened into a small smile. “You were the smartest around here and arrogant enough to let everybody know. And you did once set greenhouse four on fire, as well as my hat.” She stopped, as they had arrived at the spot where Mrs. Norris had been found. “Never got another hat as good as that one.”  
Sherlock launched into a thorough inspection of the writing on the wall as well as the floor. He rushed from one point of interest to the next, pausing in between in what seemed to be almost a petrified state as he examined a particularly fascinating piece of evidence. John stood by McGonagall's side and watched his friend as he worked.   
After merely a few minutes of investigation, Sherlock stood up straight and headed straight for a door with a sign that said 'Out of order'.  
John had enough experience with his partner's antics to not question them as he followed after giving Sherlock a small head start. He found Sherlock kneeling under one of the sinks, while a ghostly girl hovered near. “This is a girls' bathroom, you know!” she exclaimed accusingly, crossing her arms in front of her.  
“Oh, Myrtle, I see you're still around.” John said. He earned a mistrusting glare from the ghost.   
“People usually don't sound that happy when they see me. Are you- oh I remember, you're that blond kid that used to study in here!”  
“Ah, so that's were you used to vanish to, John.” Sherlock had stood up from where he'd been crouching. “I did wonder.”   
“Well, sometimes I did need a bit of time to myself. And your experiments weren't exactly quiet either.”  
“The advancement of science is never easy. Or quiet.” He replied haughtily. “Anyways, this should turn out to be a rather good column of yours. Let's go see the headmaster. He'll like to take care of this sooner rather than later.”  
“You've solved this already? Pity, I was looking forward to catching up with Hagrid.”  
“Well, he's only a pinch of floo powder away. Didn't you meet him at the Three Broomsticks the last time we were around Hogsmeade? That was only two years ago.” He turned with a dramatic whoosh of his cloak and left John and Professor McGonagall behind.   
John rolled his eyes before following after him, closely followed in turn by his former teacher.   
“He really is as good as you paint him in your column.” McGonagall commented while they tried to catch up to the tall figure before them.  
“And he really is as rude as you remember him, too. Sometimes I think I would be better off working at St. Mungo's... but you know, it never gets boring around him.” John smiled, feeling McGonagall's gaze on him. “Wouldn't trade it for the world.”  
“It doesn's surprise me in the slightest. You were hardly separable while you were at school. And from what I've heard from Kingsley Shacklebolt, you two are very good together.”  
Just a few paces ahead of them, Sherlock said “Sherbet Lemon” and the gargoyles in front of the headmaster's office stood aside. He waited slightly for them to catch up to him and then climbed the ascending stairs.  
“Ah, Mr. Holmes, very well, I gather you've solved it already. Very well, do tell me the details.” Dumbledore leaned back in his seat and looked at the younger man over the top of his half-moon spectacles.  
“It was rather disappointing, really, after you've promised me a much greater mystery, but I see now that you only wanted to prevent further harm in the most efficient way possible.” John and Minerva McGonagall had expectant looks on their faces.   
“You see, the first thing I noticed were the spiders in Mr. Lockhart's office. A fool, by the way, but you already know that. Fire him before he does any serious harm. I could probably spare John if need be. It really is quite the manageable commute by floo powder. As I was saying, the spiders were running away, which is usually not a good omen, and especially not now. The next thing was the puddle on the floor. Not that unusual outside a bathroom that is out of order. However, that particular bathroom has been out of order for many years, it's been that way at least since my time at this school. In all of the years that I traversed that corridor there had never been a wet spot outside that bathroom, so why now? The writing on the wall is a simple threat message, nothing too conspicuous about it apart from the fact that I was unable to remove it. Admittedly I am not the best at cleaning spells-” This earned a hearty chuckle from the corner where John was standing. “-but I can usually manage pretty well regardless. There is, therefore, rather dark magic at work. The final clues I found in the bathroom itself. Myrtle was so kind as to point me to the sink that has never worked, under which I found this scale-” he produced from his pocket a greyish green shimmering scale the size of his palm “-and a very interesting looking tap with a small engraved snake. I believe I have found the entrance to the Chamber of Secrets and discovered the identity of its inhabitant.” He paused for dramatic effect. “There's a Basilisk under this school.”  
A small gasp escaped McGonagall and even Dumbledore looked slightly pale. John furrowed his brow in confusion.  
“Hold on, I thought Basilisks are illegal? And they don't petrify people, they kill them with their gaze. It's been a while since Care of Magical Creatures, but that question was on my O.W.L., I remember that!”   
“You're right, John. They are illegal, which only means that whoever made this creature is supposed to be punished for it, but suppose nobody ever found out? And don't forget the puddle! Mr. Filch's cat only saw a reflection through the puddle on the floor, that's why she's petrified and not dead.” He looked to Dumbledore who seemed determined now.   
“Well, that changes things”, the headmaster said “I suspected some creature lurking somewhere in the castle but a Basilisk is another matter entirely.” He stood up and opened the window. He drew his wand and a silvery figure emerged from the tip. It was a mirror image of the phoenix sitting on its perch in the corner. “Tell Hagrid to bring me a rooster as quickly as possible.” The patronus soared out through the window which was closed promptly behind it.   
“Minerva, I need you to tell the other teachers. Tell them to carry mirrors and to look around the corners. Make sure the students are all in their common rooms. If all goes well, we'll have this resolved by morning.” McGonagall nodded and exited the room.   
Dumbledore sighed and leaned on his desk. “I suspected it fifty years ago, but I never had proof. I was lulled into a false sense of security. Something has triggered this reemergence of power. If only I knew what it was!”  
Sherlock smiled smugly. “There's one last thing I did forget to mention. Myrtle has been most forthcoming in her assistance. You should ask her about the red-haired first year girl she's seen. I think that should solve all your questions. As for us, we'll take our leave. I think John has a half-drunk cup of tea to get back to and I think I left a potion on the fire. Come John!”  
The pair left in a flourish and Dumbledore only barely heard John yell “That potion better not explode like last time! I don't care how bad your cleaning spells are, I'm not your house elf!”


End file.
